John Sayers' Recording Studio Design Forum Archive

He,

Im a studio engineer from Holland and I have a question about a design for a speaker soffit I did.
The thing is, I'm searching for a room at the moment so I don't know any real dimensions right now.
To put it in a different way, I'm just in the process of gathering information and get some skills witch I can use as soon as I get the real room.

I did gather a lot of great info on this forum about speaker soffits and I think I get it pretty much but... I'm not 100% sure. To practice my skills I designed this soffit for a room witch is: 4 meters long, 3 meters wide and 2.3 meters high.
I was wondering if there are things I forgot or that I can improve on this design.

- The baffles and speaker box will be made out of 2 cm thick MDF
- The frames will be build with 5 by 10 cm thick wood.
- The hole frame will be filled with 10 cm Rockwool 201 (except for the 'bass hole')
- The bottom space is for hangers
- The hight is 230 cm
- The baffle is 106 cm wide
- The speaks will be (Active) dynaudio BM6a
- There is 2 mm rubber in the speaker box to make it a tight fit.
- There is a ventilation hole of 4 by 20 cm on the top and bottom of the speaker box for ventilating the speakers

My question is basically: Im I on the right track with this design or not.

Grtz Person from holland

ps. I hope not to offend anybody because it's just a learning exercise, if so: my apologies.

Hi there "Person from holland"! Welcome to the forum!

- The baffles and speaker box will be made out of 2 cm thick MDF

Excellent!

- The frames will be build with 5 by 10 cm thick wood.

Right.

- The hole frame will be filled with 10 cm Rockwool 201 (except for the 'bass hole')

What "bass hole"? Soffits should never by built as ported cabinets!

- The bottom space is for hangers

Right

- The hight is 230 cm

That will depend on the room! You say you don't have a room yet, so the actual height of the soffit will be defined by the height of the inner-leaf ceiling at the point where the soffits are.

- The baffle is 106 cm wide

That also depends on the room size.

- The speaks will be (Active) dynaudio BM6a

Those are rear-ported speakers, as far as I know, and should not be soffit mounted. You should only soffit-mount speakers that are front ported or not ported at all.

- There is a ventilation hole of 4 by 20 cm on the top and bottom of the speaker box for ventilating the speakers

Right, but you also need to leave a "chimney" through the insulation, to allow for free flow of air: The easiest way to do that is just to shape a wire "cage" using chicken wire, so prevent the insulation from blocking the ventilation air path.

- Stuart -

>>You should only soffit-mount speakers that are front ported or not ported at all.

Is this an absolute or is there any wiggle room?

ADVthanksANCE

-Jack

Is this an absolute or is there any wiggle room?

It MIGHT be possible to soffit-mount some rear-ported speakers, if you do it carefully, either by plugging the port or by having a large enough volume inside the soffit to deal with that. But then you'd lose the low-frequency extension that the port provides, and be restricted to the actual un-ported frequency response of the drivers. Plugging the port brings its own issues: it might change the response curve of the woofer, since it would be working against a different impedance load.

So theoretically it could work, but it would be "trial and error" to get it right, and different speakers would act in different ways when in stalled in the exact same soffit.

What speakers are you thinking of soffit-mounting?


- Stuart -

>> What speakers are you thinking of soffit-mounting?

Alesis Monitor Two's, but after reading your message, I'll definitely go with something else.

Right now, I'm using my original Klipsch Heresy's that I bought new in 1977 along with an older small Klipsch sub that helps out below 50 hz or so.

I had forgotten how great they sound. I am finding them really easy to listen to, even for long periods as long as I don't get them too loud.

They are sealed and are probably a much better choice for soffit mounting.

I'm going to post a topic on my plans for my new studio build as soon as I get a little better at using Sketchup.

Thanks very much for your valued input and for sharing your experience and expertise with all of us.

-Jack